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Peggy Biga, PhD

My research questions focus on the mechanisms regulating differential growth paradigms. In other words, we are interested in learning how some organisms have the ability to continually grow new muscle fibers throughout life, while other organisms cannot.

Specifically, we aim to identify novel regulators of muscle cell growth and to determine how myogenic progenitor cells contribute to regeneration/repair in response to several common stimuli, including injury or stress, nutritional alterations, and environmental contamination. The following are primary questions we are working to answer:

To address this question, we utilize several fish models using comparative approaches. Two closely-related fish species that exhibit opposing growth paradigms, giant danio:indeterminate and zebrafish:determinate-like, appear to regulate growth in different ways. We are using these species in a parallel manner to understand why some satellite cells become new muscle cells, while others join pre-existing cells. We are using normal growth, enhanced growth, and injury-induced scenarios to identify these parameters.

Using indeterminate growing models-giant danio and rainbow trout-we are investigating how quiescent satellite cells are activated following various different stressors (injury, increased lipid signaling and deposition, and infection).

Using recently validated primary myoblast cultures, we are investigating the presence of embryonic-like myogenic precursor cells in adult organisms that exhibit indeterminate growth potential. We have identified specific pathways in adult indeterminate growing organisms that are present only during embryonic myogenesis in determinate growing organisms. We aim to demonstrate that these pathways ensure increased myofiber number potential in indeterminate growth models.

What role does myostatin play outside of muscle growth regulation?

We are focusing on the role myostatin plays in lipid metabolism, insulin signaling, and cellular growth. We are interesting in identifying the role of the extracellular matrix in regulating mstn signaling.

We are also analyzing the co-regulation of the stress and growth axes in relation to myostatin in Salmonids.